Are GaAs MOSFETs worth building? A model-based comparison of Si and GaAs n-MOSFETs

A two-dimensional self-consistent Monte Carlo device modeling program is used to determine the behavior of submicron GaAs n-MOSFETs with semiconductor-insulator properties idealistically assumed to be of the same high caliber as present-day Si-SiO/sub 2/ interfaces. Compared to their conventional Si substrate counterparts, GaAs n-MOSFETs have similar transconductances and transit times, casting doubt on the notion that GaAs n-MOSFETs will ever outperform Si n-MOSFETs. Although alternative novel device designs better suited for exploiting the transport properties of bulk GaAs cannot be precluded, it is argued that the technological challenges of actually manufacturing GaAs devices further favor the use of silicon. These results can be predicted by considering the full semiconductor band structure away from the band extrema and suggest that differences among various semiconductors and carrier types are of diminishing importance for submicron devices.<>